As the population in the United States becomes older, and medicine provides increasing numbers of highly technological life-sustaining treatments, concern about allocation of medical resources becomes more pressing and individual treatment choices become more difficult. Medical ethicists have stated that the use of life-sustaining treatments toward the end of life should be based upon expected medical benefit and patient preference. We have, however, no consensus among medical practitioners in the United States about what is sufficient medical benefit to justify treatment. Furthermore, we have little insight into the concerns that underlie patients' life-sustaining treatment choices and whether we could address these concerns through other kinds of car. A study is therefore proposed 1) to survey 425 medical and health policy leaders to begin to provide more clearly defined and agreed upon definitions of the medical benefits we might wish to achieve, 2) to interview in a longitudinal prospective study, over two and one-half years, 375 elderly individuals (over age 65) with severe heart or lung disease or metastatic carcinoma, to explore to what extent patients' treatment preferences are congruent with medical benefit as defined by these medical leaders and to what extent they are based upon concerns that might be addressed by other appropriate kinds of care, and 3) to determine through interview of attending physicians and the review of hospital records, to what extent the use of life-sustaining treatment is based upon expectation of medical benefits and patient preferences as suggested by ethical guidelines. Thus, through better definition of medical benefits and understanding of patients preferences, this project is intended to improve the quality of patient care and resource allocation toward the end of life.